22-year-old Kansas City black man, Fredrick Demond Scott, has been charged with murder in the deaths of two older white men in ambush-style attacks. Scott is also the suspect in the slayings of three other white men ranging in age from 57 to 67. If convicted of those crimes, Scott meets the FBI’s requirement of a serial killer, The Kansas City Star reports.

All five men were killed in similar ways, the report notes: “[M]ost from behind, in surprise attacks as they walked dogs, visited parks and, in one case, walked down a city street.”

Scott’s criminal history includes threatening a mass shooting at the Center Alternative School in January, 2014, when he said, “I want to shoot the school up, Columbine-style.” He also stated he wanted to “kill all white people” and then commit suicide. For making that threat, Scott was sentenced to 180 days in jail but it was suspended and he was given probation, ordered to stay away from the school, and was placed under “intense” supervision, the report states.

Scott somehow ended up graduating from the school, according to his mother who said she doesn’t remember him making that threat, nor does she think his crimes have anything to do with race:

Scott’s mother said in an interview with The Star that he refused to get treatment for his paranoid schizophrenia but did not show any hatred toward white people. Scott was cited in Kansas City municipal court in 2013 for assault on his mother, accused of shoving her several times. She called police, hoping tough love would help him, she said.

“As far as I know Fredrick never had a problem with white people,” his mother said. “He would do odd jobs for people and some of those people were white men.”

Scott told detectives that he has remained distraught over the shooting death of his half brother during an attempted robbery in 2015. The shooter in that incident was noted as black. A co-worker of Scott’s at the local Burger King said, “He felt like his brother was the only person who loved him. It really damaged him.”

Police say they aren’t sure of Scott’s motivations for murdering these men.

Below is the county prosecutor announcing the charges and more details on the killings: